Fluid sensor



Sept. 6, 1966 E. R. PHILLIPS 3,270,960

FLUID SENSOR Fil ed Sept. 11, 1964 FLUID SOURCE 2a 34\ I 19 v 32 26 OUTPUT Fugg SEN 13 FIG. 1 H/ d Q 22\ M l 0 /V// Q50 A 1 FLUID SOURCE FIG. 2

INVENTUR EDWIN R. PHILLIPS W 4AM ATTORNE Y5 United States Patent 3,270,960 FLUID SENSOR Edwin R. Phillips, Rosemont, Pa., assignor to Sperry Rand Corporation, New York, N.Y., a corporation of Delaware Filed Sept. 11, 1964, Ser. No. 395,796 16 Claims. (Cl. 235201) The present invention relates to new and novel means for broadly sensing the presence of a selectively generated fluid jet stream without permitting contamination of the sensing mechanism by material carried by said stream, and more particularly, relates to means for sensing the presence of an aperture in a record car-d or the like by a novel fluid principle.

The pneumatic or other fluid sensing of punched record cards is well known in the art and basically is carried out by two different kinds of apparatus. The first is structure wherein a fluid jet is generated on one side of a record card having a direction of flow suchthat it passes through an aperture in the card to impinge, via a fluid recovery channel, on a fluid sensing means situated on the opposite side of the card. One disadvantage of this kind of sensing circuit is that when the jet travels through the card hole, card dust or other contamination can become entrained therein which may reach the sensor and thus ultimately adversely affect its operation. The second basic type of prior art apparatus is one wherein a source of fluid is situated on one side of the card and is connected via a fluid channel to an orifice on the same side which in turn is located so as to be either blocked by a card imperforate surface portion adjacent thereto, or unblocked by a card perforation aligned therewith. A pressure sensing means is connected to the fluid channel which is responsive to certain threshold value of pressure therein. Thus, when the fluid orifice is blocked, the pressure in the fluid channel rises to a value sufficient to place the sensing means in one of its states, while an unblocked fluid orifice permits enough fluid to escape from the channel so as to decrease the fluid pressure therein and thereby place the sensing means in another of its states. Although this second prior art device does, in most cases avoid the problem of sensor contamination caused by dust or the like being carried inwardly of the connecting fluid channel, it has one disadvantage in that there is a substantially stagnant body of fluid generally being maintained in the connecting channel whenever an imperforate surface of the card body is adjacent to the orifice. Although very often this stagnant body of fluid has no disabling effect on the sensor, in some environments it may tend to clog the sensor with such contamination as may inadvertently find its way into the channel. Another disadvantage is that a good seal is required between the card and housing containing the orifice in order to insure proper operation. The mechanism to obtain sealing can be expensive besides tending to reduce the reliability of the device. A further disadvantage of this second type of prior art device is that the sense or polarity of the fluid channel pressure is inverted with respect to the presence of a card hole, that is to say, when a card perforation is aligned with the orifice, the fluid channel pressure is less than its value when the orifice is blocked. For some environments, this may constitute a logical disadvantage which can only be overcome by incorporating additional logical elements, such as inverters, into the device.

The present invention provides means to obviate the above described disadvantages of each of the prior art fluid sensing devices. In general, a fluid jet stream from a first source is generated on one side of a record card or the like which passes through an aperture or perform-ation therein to impinge upon an orifice on the opposite side ice of the card. Connected to said orifice is a fluid recovery channel or chamber which in turn is continuously supplied with clean fluid by a second source such that static fluid pressure in the recovery channel varies according to the rate of fluid flow through the orifice. Also connected to the fluid recovery channel is a fluid pressure sensor means. Suflicient space is maintained at all times between the orifice housing and the record card so that a clean fluid flow volume always exists therebetween even when an imperforate portion of the card surface is directly opposite said orifice. Thus, a substantial flow of clean fluid normally occurs in the recovery channel because of the absence of record card sealing at the orifice, which flow permits almost continuous purging of contamination therein. Furthermore, the resulting free escape of clean fluid from said orifice and over the card surface keeps the static pressure in the recovery channel at a value low enough to maintain the sensor means in one of its states. However, at any time when said externally generated fluid jet stream impinges on said orifice as by the alignment therewith of a card perforation (or the absence of a card in the sensing station), the effective resistance at said orifice to clean air flow therethrough from the recovery channel increases to cause the build up of clean fluid pressure in the recovery chamber to a degree necessary to change the state of the sensor means. The energy of the externally impinging fluid jet can be adjusted relative to that of the clean fluid issuing from the orifice, which the former opposes, so that the only fluid actually in the recovery chamber at any time is from the second clean fluid source connected thereto. Consequently, no card contamination can be carried by the fluid jet into the fluid recovery channel and then to the sensor. Furthermore, the alignment of a card aperture (usually indicating a binary 1 code value) with the orifice causes a rise in recovery channel pressure which in turn can be conven iently interpreted as representing a binary 1 value in a data processing system.

Thus, one object of the present invention is to provide a new and improved fluid sensing means for determining the presence of an aperture in a record card or the like.

Another object of the present invention is to broadly provide means for sensing the presence of a selectively applied fluid jet in a way to prevent any contamination in said jet from fouling the sensor equipment.

A further object of the present invention is to provide fluid sensing means utilizing an externally generated fluid jet which impinges upon an outlet in a fluid recovery channel to which in turn is connected a source of fluid and a sensing means.

These and other objects of the present invention will become apparent during the course of the following description to be read in view of the drawings, in which:

FIGURE 1 is a view showing a preferred embodiment of the invention; and

Figure 2 is a plan view of a pure fluid amplifier which may be conveniently utilized as the fluid pressure sensor in FIGURE 1.

FIGURE 1 shows the present invention as adapted for particular, although not exclusive, use in the pneumatic sensing of an aperture 10 located in a web 12 which may in fact be a punched record card of the type used in data processing systems. Said card 12 is situated in a sensing station 13 at usually atmospheric or other environmental pressure wherein it may either be stationary or given motion, as for example, during a sorting operation. Located on one side of card 10 is a first housing 17 in one surface of which is a fluid nozzle orifice 14 having a predetermined flow area and which is oriented such that an air jet 15 issuing therefrom can pass through aperture 10 to the other side of card 12. Orifice 14 in turn is connected by means of a channel 16 to a source 18 of pressurized air used in creating the jet flow 15. Source 18 may either be continuously operated so that air jet is always present, or alternatively may be selectively operated only when a card 12 is inserted into station 13. That surface of card 12 which is next to orifice 14 may be either in abutment therewith or may be spaced apart therefrom if the card is in motion. 7

Located on the opposite side of card 12 so that it is next to the other major card surface 22, is a second housing 19 containing a second fluid nozzle orifice 24 of predetermined flow area and which is in alignment with orifice 14 so as to receive air jet stream 15 as it passes through aperture 10. The flow area of orifice 24 can be at least 2.5 times that of orifice 14. The housing surface in which orifice 24 is located should be spaced apart some suflicient distance a from card surface 22 such that there is at all times a fluid flow volume therebetween in order that orifice 24 is never completely blocked by an imperforate card surface portion directly opposite thereto. Card feed rollers 21 are shown as being one means for maintaining the required spacing d. Orfice 24 in turn is connected to a fluid receiving channel or chamber 26 of some predetermined volume which, in the preferred embodiment, takes the shape of a straight elongated conduit having its other end connected via a fluid restriction 28 to some fluid source preferably at substantially constant pressure. Source 30 may in fact be derived from or identical to source 18 if so desired, but is preferably in constant operation so as to provide a steady state flow 29 of fluid through restriction 28. Restriction 28 in turn acts as a resistance limiting the amount of fluid flow from source 30'into fluid recovery channel 26. In other words, it acts as a pressure dropping means whose function is similar to the function of a load resistance in an electrical circuit. Consequently, the fluid pressure in recovery channel 26 immediately downstream from restriction 28 can vary according to the rate of fluid flow through said channel 26 even though source 30 is substantially constant pressure device. Source 30 acting in conjunction with restriction 28 may therefore be conveniently labelled a variable pressure source whose output pressure varies according to the degree of fluid flow therefrom. Other variable pressure sources may obviously be employed if so desired.

Also connected with fluid recovery channel 26, as by means of a conduit 32, is a static pressure sensing means 34 which is responsive to at least two levels of static fluid pressure in channel 26. The exact function required of sensor 34 is determined, of course, by the environment in which the invention is utilized. It may, for example, convert input fluid static pressure into a different static or dynamic fluid pressure output, into electrical energy, or into mechanical energy (thus acting as an energy transducer). Generally speaking, sensor 34 should at least be a two state device such that it is placed in one of its states in response to a first static pressure in channel 26,

and into another state in response to a second pressure therein. Another way of viewing its operation is to say that it is actuable to a first of its states for a static pressure level below a certain predetermined threshold value, and is actuable to a second state for a static pressure equal to or above said predetermined threshold value. Alternatively, if, in certain applications of the invention, the static pressure in channel 26 is continuously variable between little static pressure is built up in said channel 26 which 'keep's s'ensor34 in a first of its states. This condition occurs either when an imperforate portion of surface 22 is opposite orifice 24, or when there is no jet 15 issuing from orifice 14. Since clean fluid continually issues from orifice 24 at this time, any dirt, dust, or other contamination will tend to be prevented from entering orifice 24, or removed therefrom. However, whenever a card aperture 10 becomes aligned with an activated jet 15 from orifice 14, said jet passes therethrough to impinge upon the flow area of orifice 24 in direct opposition to the flow 29 or clean air coming from source 30. This impingement of jet 15 at the mouth of orifice 24 effectively reduces the flow area thereof so as to increase the resistance to flow 19. It actually produces the same result as if orifice 24 were closed or blocked by placing a finger or the like thereover. This in turn reduces the amount of flow 29 in recovery channel 26 so as to lessen the pressure drop across restriction 28, or in other words, to raise the static pressure therein. The energies of the fluid from sources 18 and 30 are adjusted, relative to the various dimensional parameters of the system, such that little, if any, of jet 15 actually enters recovery channel 26. By keeping s-ufiiciently small the entrained channel 26 volume, as found between orifice 24 and conduit 32, the additional fluid necessary to raise the pressure in this volume to a degree required to actuate sensor 34 to another of its states can be obtained solely from the clean air coming from source 30. Consequently, contaminated jet 15 fluid does not actually reach sensor 34 which in turn is responsive only to a change in clean fluid pressure.

Slightly different arrangements of structure may be employed to carry out the function of FIGURE 1. For example, fluid source 30 and restriction 28 can be interchanged in position with sensor 34 so that clean fluid enters channel 26 intermediate its opposite ends. Also, FIGURE 1 could be modified by connecting source 30 and restriction 28 to channel 26 at a second intermediate point different from the point to which channel 32 is connected, and blocking the end of channel 26 opposite to orifice 24. a

As but one example of a sensor means 34 which may be employed in the structure of FIGURE 1, FIGURE 2 shows the plan view of a typical pure fluid amplifier 40 which is admirably suited for converting static fluid pressure input into a dynamic fluid output. Pure fluid .amplifiers are a recent development and in general operate on the principle that a relatively high energy fluid stream, called the power stream, can be deflected without losing its integrity so as to vary its discharge quantity through one or more output channels by means of an input control fluid signal of lesser energy impinging thereon. A plurality of interconnected fluid channels are formed in a body of fluid impervious material, such as clear plastic or the like. A power stream input channel 42 is supplied with relatively high energy fluid via a port 44 and discharges via a nozzle 46 into a fluid interaction chamber 48. Branching from the opposite end of chamber 48 are two power stream output channels 56 and 52 which are joined together at a divider tip 54 asymmetrically disposed to the right of the center line of nozzle 46. Thus, the normal undeflected path of power stream jet fluid issuing from orifice 46 is into power stream output channel 50 from whence it may be directed to some form of utilization means, or alternatively, back to the source of power stream fluid (not shown in FIGURE 2). In order to selectively deflect power stream fluid into output channel 52, a single control stream input channel 56 is provided which enters one side of interaction chamber 48 via a nozzle 58. The input 60 of channel 56 is connected to the output of channel 32 in FIGURE 1. Fluid static pressure applied .to the input 60 from channel 32 is converted into kinetic energy in the form of a jet issuing from nozzle 58 to impinge, at about a right angle, upon the power stream fluid coming from nozzle 46. As is well known, the impingement of control stream energy upon the power stream causes the deflection of the latter away from channel 50 and into channel 52, whose output in turn may be connected to utilization means responsive to such increased fluid flow. Amplifier 46 may in fact be designed to provide either a proportional deflection of power stream fluid in response to a proportional change in the control input static pressure, or may alternatively be designed to entirely deflect the power stream into output channel 52 upon a rise in control static pressure to some predetermined threshold value. However, although FIG- URE 2 shows one form of fluid sensor which may be utilized, other well known types are suitable.

As pointed out above, the present invention is particu larly useful in a novel way for hole sensing in record cards or the like, but its utility is much broader since it generally provides means to broadly sense the presence or absence of a fluid jet stream, and/ or magnitude thereof. Therefore, while a preferred embodiment of the present invention has been shown and described, modifications may obviously be made thereto by persons skilled in the art without departure from the novel principles as defined in the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Fluid apparatus for sensing the presence of an aperture extending through a body, which comprises:

(a) a region in which the body can be selectively placed;

(b) a first fluid orifice having -a predetermined first flow area which is located to one side of said region and oriented such that a fluid jet stream issuing therefrom will pass through a body aperture in alignment therewith to emerge at the opposite side of said region;

(c) a second fluid orifice having a predetermined second flow area which is located at the opposite side of said region in alignment with said first fluid orifice for receiving a fluid jet stream therefrom, said second orifice being spaced from the body a distance suflicient to provide a predetermined third flow area therebetween;

(d) a fluid recovery channel of predetermined volume connected to said second fluid orifice;

(e) fluid static pressure sensing means including means directly connected to said fluid recovery channel, said sensing means being in at least a first or a second state in response to a fluid static pressure of a first or a second value, respectively, in said fluid recovery channel; and

(f) a first pressurized fluid source connected to said first fluid orifice for producing a first fluid jet stream therefrom, and a second pressurized fluid source connected to said fluid recovery channel for producing a second fluid jet stream from said second fluid orifice, where the energies of the fluid from said first and second fluid sources are such, relative to each other, to said recovery channel predetermined volume, and to said first, second, and third flow areas, that fluid in said recovery channel any time substantially comes only from said second fluid source and is at either said one or said second static pressure value in response to the respective absence or presence of said first fluid jet stream impingement on said second fluid orifice so that fluid from said second fluid source is the sole fluid acting on said pressure sensing means.

2. Apparatus according to claim 1 wherein said second flow area is at least two and one half times the size of said first flow area.

3. Apparatus according to claim 1, wherein said fluid recovery channel is an elongated fluid conduit having a first end thereof connected to said second fluid orifice and a second end thereof connected to said second fluid source, with said sensing means being connected to said fluid recovery channel intermediate said first and second ends.

4. Apparatus according to claim 1, wherein said second fluid source comprises the combination of a source of relatively constant pressure fluid connected to a fluid restriction which in turn is connected to said fluid recovery channel.

5. Apparatus according to claim 3, wherein said second flow area is at least two and one half times the size of said first flow area.

6. Apparatus according to claim 4, wherein said second flow area is at least two and one half times the size of said first flow area.

7. Fluid apparatus for sensing the presence of a first fluid jet stream of predetermined energy, which comprises:

(a) a fluid orifice having a predetermined flow area which is located in alignment with the first fluid stream for receiving same;

(b) a fluid recovery channel of predetermined volume connected to said fluid orifice;

(c) fluid static pressure sensing means directly connected to said fluid recovery channel by means of a closed conduit, said sensing means being in at least a first or a second state in response to a fluid static pressure of a first or a second value, respectively, in said fluid recovery channel; and

(d) a source of pressurized fluid connected to said fluid recovery channel for causing a second fluid jet stream to issue from said fluid orifice in opposition to the first fluid jet stream, where the energy of said second fluid jet stream is such, relative to the energy of the first fluid stream, to said recovery channel predetermined volume, and to said predetermined flow area, that fluid in said fluid recovery channel at any time substantially comes only from said source and is at either said one or said second static pressure value in response to the respective absence or presence of the first fluid jet stream so that fluid from said second fluid source is the sole fluid acting on said pressure sensing means.

8. Apparatus according to claim 7, wherein said fluid recovery channel is an elongated fluid conduit having a first end thereof connected to said fluid orifice and a second end thereof connected to said fluid source, with said sensing means being connected to said fluid recovery channel intermediate said first and second ends.

9. Apparatus according to claim 7 wherein said fluid source comprises the combination of a source of relatively constant pressure fluid connected to a fluid restriction which in turn is connected to said fluid recovery channel.

10. Apparatus according to claim 9, wherein said fluid recovery channel is an elongated fluid conduit having a first end thereof connected to said fluid orifice and a second end thereof connected to said fluid source, with said sensing means being connected to said fluid recovery channel intermediate said first and second ends.

11. Fluid apparatus comprising:

(a) means for selectively generating a first fluid jet stream of predetermined energy having a predetermined flow path;

(b) a fluid orifice having a predetermined flow area which is located in alignment with said flow path for receiving said selectively generated first fluid jet stream;

(0) a fluid recovery channel of predetermined volume connected to said fluid orifice;

(d) a fluid static pressure sensing means including means directly connected to said fluid recovery channel, said sensing means being in at least a first or a second state in response to a fluid static pressure of a first or a second value, respectively, in said fluid recovery channel; and

(e) a source of pressurized fluid connected to said fluid recovery channel for causing a second fluid jet stream to issue from said fluid orifice in opposition to said selectively applied first fluid jet stream, where the energies of said first fluid jet stream and said second fluid jet stream are such, relative to each other, to said predetermined volume, and to said predetermined flow area, that fluid in said fluid recovery channel at any time substantially comes only from said source and is at either said one or said second static pressure value in response to the respective absence or presence of said first fluid jet stream so that fluid from said second fluid source is the sole fluid acting on said pressure sensing means.

12. Apparatus according to claim 11 wherein said fluid recovery channel is an elongated fluid conduit having a first end thereof connected to said fluid orifice and a second end thereof connected to said fluid source, with said sensing means being connected to said fluid recovery channel intermediate said first and second ends.

13. Apparatus according to claim 11, wherein said fluid source comprises the combination of a source of relatively constant pressure fluid connected to a fluid restric- 7 tion which in turn is connected to said fluid recovery channel.

14. Apparatus according to claim 11 wherein said first fluid jet stream generating means comprises the combination of a continuously operating fluid stream source and a barrier body with at least one aperture therein which can be selectively aligned with the stream from said last named source.

15. Fluid apparatus for sensing the presence of an aperture in a record card, which comprises:

(a) a first fluid orifice having a predetermined first (b) a second fluid orifice having a predetermined second flow area which is in alignment with said first fluid orifice but is spaced apart therefrom;

(c) means to support a record card between said first and second fluid orifice at a distance from said second fluid orifice suflicient to provide a predetermined third flow area therebetween;

(d) an elongated fluid conduit of predetermined volume having a first end thereof connected to said second fluid orifice and a second end thereof adapted for connection to a source of fluid;

(e) fluid static pressure sensing means connected to said fluid conduit at a point intermediate said first and second ends, said sensing means being in at least a first or a second state in response to a fluid static pressure of a first or a second value, respectively, in said fluid conduit;

(f) a first pressurized fluid source connected to said first fluid orifice for producing a first fluid jet stream therefrom; and

(g) a second source of relatively constant pressure fluid connected to a fluid restriction which in turn is connected to said second end of said fluid conduit, where the energies of the fluid from said first and second sources are such, relative to each other, to said predetermined fluid conduit volume, and to said first, second, and third flow areas, that fluid in said fluid conduit at any time substantially comes only from said second source and is at either said one or said second static pressure value in response to the respective absence or presence of said first fluid jet stream impingement on said second fluid orifice.

16. Apparatus according to claim 15, wherein said second flow area is at least two and one half times the size of said first flow area.

References Cited by the Examiner UNITED STATES PATENTS 3,057,974 10/1962 Cohen 200-46 3,103,850 9/1963 Khoury et al. -r 20972 3,169,639 2/1965 Bauer et a1. 20974 3,191,008 6/1965 Wadey 23561.1l

FOREIGN PATENTS 1,175,053 11/1958 France. 1,362,309 4/1964 France.

RICHARD B. WILKINSON, Primary Examiner.

LEO SMILOW, Examiner.

W. F. BAUER, Assistant Examiner. 

1. FLUID APPARATUS FOR SENSING THE PRESENCE OF AN APERTURE EXTENDING THROUGH A BODY, WHICH COMPRISES: (A) A REGION IN WHICH THE BODY CAN BE SELECTIVELY PLACED; (B) A FIRST FLUID ORIFICE HAVING A PREDETERMINED FIRST FLOW AREA WHICH IS LOCATED TO ONE SIDE OF SAID REGION AND ORIENTED SUCH THAT A FLUID JET STREAM ISSUING THEREFROM WILL PASS THROUGH A BODY APERTURE IN ALIGNMENT THEREWITH TO EMERGE AT THE OPPOSITE SIDE OF SAID REGION; (C) A SECOND FLUID ORIFICE HAVING A PREDETERMINED SECOND FLOW AREA WHICH IS LOCATED AT THE OPPOSITE SIDE OF SAID REGION IN ALIGNMENT WITH SAID FIRST FLUID ORIFICE FOR RECEIVING A FLUID JET STREAM THEREFROM, SAID SECOND ORIFICE BEING SPACED FROM THE BODY A DISTANCE SUFFICIENT TO PROVIDE A PREDETEMINED THIRD FLOW AREA THEREBETWEEN; (D) A FLUID RECOVERY CHANNEL OF PREDETERMINED VOLUME CONNECTD TO SAID SECOND FLUID ORIFICE; (E) FLUID STATIC PRESSURE SENSING MEANS INCLUDING MEANS DIRECTLY CONNECTED TO SAID FLUID RECOVERY CHANNEL, SAID SENSING MEANS BEING IN AT LEAST A FIRST OR A SECOND STATE IN RESPONSE TO A FLUID STATIC PRESSURE OF A FIRST OR A SECOND VALUE, RESPECTIVELY, IN SAID FLUID RECOVERY CHANNEL; AND 